A washing apparatus is known, for washing and heat-disinfecting surgical instruments, laboratory instruments or other, contained in baskets carried by a trolley, container or other trolley-type movement device.
This known apparatus has a washing chamber of the oblong tunnel type, having an entrance door on the dirty side and optionally an exit door towards the clean side, and an inclinable support plane, substantially on the level of the bottom of the washing chamber, provided with two parallel runners along which the instrument-carrying trolley is inserted slidingly inside the washing chamber.
The known washing apparatus has a main distribution circuit for the washing liquid, provided with a pump and pipes that take the washing liquid inside the washing chamber.
In the known washing apparatus a plurality of distribution elements are provided, to distribute the washing liquid, and are disposed along the lateral and bottom walls, and the upper wall, to direct the flow of washing liquid towards the trolley.
The trolleys or containers used in these known washing apparatuses consist of a frame, which supports said baskets and which also supports a plurality of washing impellers. The frame is hollow inside and thus functions as a secondary distribution circuit of the washing liquid, putting a delivery element of washing liquid connected to the main distribution circuit into hydraulic communication with said impellers.
Moreover, a hydraulic pipe is provided, and is part of the main distribution circuit and disposed on the level of the support plane, laterally or below on the bottom of the washing chamber. The pipe is selectively connected to the delivery element of the secondary distribution circuit of the washing liquid provided on the trolley or container.
Once the trolley has been inserted and the doors closed, a control unit activates the connection of the pipe to the delivery element of the trolley and starts the washing cycle.
The movement of the trolleys from and to the apparatus is described for example in the Italian patent applications in the name of the present Applicant, UD2005A000193 and UD2006A000232.
The solution where the hydraulic pipe is disposed on the bottom of the washing chamber has the following disadvantages:                interference of the hydraulic pipe with the impellers, which are thus eliminated or reduced in diameter, but to the detriment of productivity and the effectiveness of the wash;        need to provide a lower compartment, made under the washing chamber, to house the hydraulic pipe and the auxiliary hydraulic and electric connections;        risk of leakages of washing liquid from the lower compartment to the floor around the washing apparatus;        reduced exploitation of most of the washing liquid in the delivery element, due to the contrasting action of the force of gravity during the thrust from the bottom upwards, with reduced outlet pressure to the impellers and possible inefficiency of the wash.        
The solution where the hydraulic pipe is disposed laterally has the following disadvantages:                risk of lateral interference with the baskets or the impellers;        need for a counter-thrust element or member, on the side opposite that where the hydraulic pipe is connected, to prevent the trolley from moving or turning over once the pipe is connected;        unequal distribution of the washing liquid in the secondary distribution circuit of the trolley, due to the lateral position of the delivery element, with consequent lack of homogeneity in the outlet pressure of the washing liquid to the impellers and possible inefficiency of the wash.        
Purpose of the present invention is to achieve a washing apparatus which overcomes the disadvantages of the state of the art and which exploits effectively most of the washing liquid entering the secondary distribution circuit.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.